The present invention relates to a method and a device for cogenerating heat and work.
It relates in particular to a cogeneration method implemented by means of a turbine, particularly a gas turbine.
More specifically, the method consists of using the hot combustion gases generated by the gas turbine to exchange heat with an industrial facility to produce an endothermic reaction for example.
Prior cogeneration methods consisted of using the hot combustion gases leaving the turbine, which are generally at a pressure close to atmospheric pressure, to generate for example steam under pressure by heat exchange produced in an exchanger traversed by these hot gases and through which a fluid such as water flows. These systems can feed a steam distribution system that can supply various industrial facilities such as the heating of distillation column reboilers.
The drawback of such a method is that the temperature of the hot gases is insufficient to heat industrial facilities operating at relatively high temperatures, for example greater than 500° C.
Moreover, direct utilization of the hot gases leaving the gas turbine is difficult since the pressure loss at the outlet of the gas turbine must remain very low, since these gases are leaving at a pressure close to atmospheric pressure and any pressure loss, even a relatively small loss, greatly interferes with gas turbine performance.
The proposal has also been made of using such hot combustion gases, as better described for example in French Patent Application No. 2,825,995 or in French Patent Application No. 2,675,498 by the applicant, to ensure reforming of a gas feedstock, but the drawback is that when the hot gases are sent to the turbine after heat exchange, they have given off heat and are substantially cooled. This being the case, the mechanical power produced by the turbine is significantly less. Moreover, the initial dimensions of the turbine and of the blades on an expansion turbine are not adapted to the new conditions under which the pressurized hot gases sent to it/them are admitted.